Osteopoietic chimerism and histomorphometry. (A) Osteoblast (OB) chimerism, determined by immunohistochemical staining for GFP expression, in the epiphysis (left) and metaphysis (right) at 1 and 4 weeks after cytokine treatment. n = 5 for each cytokine group at each time point; 8 sections per mouse were analyzed. (B) Histomorphometric analyses of bone from G-CSF–, GH-, and saline-treated mice obtained at 1 (left) and 4 (right) weeks after completion of the cytokine regimen. n = 5 for each cytokine group. (C) Osteocyte (OC) chimerism, determined by immunohistochemical staining for GFP expression, in the epiphysis (left) and metaphysis (right) at 1 and 4 weeks after cytokine treatment. n = 5 for each cytokine group at each time point; 8 sections per mouse. All data are presented as mean ± SE. Statistically significant relationships are indicated. ***P < .001, **P < .01, and *P < .05 compared with saline group at the same time point.